Integrated control of cardio - resp - renal Flashcards
(14 cards)
What physiological changes occur during exercise?
↑ CO₂, ↓ pH (via H₂CO₃), ↑ lactic acid, ↑ temperature, ↑ muscle movement, fluid and electrolyte loss (Na⁺, Cl⁻).
How does the body respond to exercise?
↑ HR and BP to improve perfusion, redirects blood to active tissues, ↑ ventilation to remove CO₂, retains Na⁺/Cl⁻/H₂O to maintain volume.
How do proprioceptors regulate cardiac output during exercise?
Proprioceptors sense movement → signal medulla → ↓ parasympathetic, ↑ sympathetic tone → ↑ HR, ↑ Cardiac Output, vasoconstriction in inactive organs.
Where are baroreceptors located and what do they do?
Located in carotid sinus, aortic arch, and renal arteries. Signal medulla; if BP ↑ → parasympathetic activated, if ↓ → sympathetic activated.
Describe sympathetic regulation of blood flow during exercise.
Noradrenaline → α₁ receptors (cardiac) →PLC ↑ IP₃, DAG → ↑ Ca²⁺ → contraction. In smooth muscle, NA → β₂ → ↑ cAMP → inhibits MLCK → vasodilation to muscles.
What causes local regulation in blood flow?
Local Regulation of Blood Flow
If tissue is not working particulaerly hard then the rings of muscle called sphincters clamp around the blood vessels restricting the amount of blood sent to the tissue. If it is working hard then around they will produce CO2 lactic acid and the ion channels on the sphincter will respond to substrates and relax the sphincter allowing increased blood flow.
How is local blood flow regulated
Increased levels of CO2, lactic acid, adenosine, and temperature promote vasodilation.
Decreased levels of oxygen lead to increased blood flow to tissues.
Increased substrates or decreased oxygen leads to arteriole and precapillary relaxation resulting in more blood flow to capillary beds
Remember that control of this is regulated by medulla oblongata and that when increasing heart rate first parasympathetic is deactivated and then sympathetic is activated
What is the skeletal muscle pump and its role?
Muscle contraction squeezes veins → promotes venous return → ↑ CO. One-way valves prevent backflow.
What is the thoracic pump and how does it support cardiac output?
Inhalation ↓ thoracic pressure, ↑ abdominal pressure → venous return. Exhalation reverses this. Supports Starling’s Law (↑ venous return = ↑ CO).
How is ventilation chemically regulated?
↑ PaCO₂ → central chemoreceptors; ↓ PaO₂ or ↓ pH → peripheral chemoreceptors → signal medulla → ↑ breathing rate.
What does the Frennic nerve do
Frennic nerve innervates the diaphragm using ACH to nicotinic receptors. Things are nicotinic when you need things FAST. couldn’t be muscarinic as its too slow
What are adrenaline’s effects on the body during exercise?
↑ HR and contractility (β₁), bronchodilation (β₂), vasoconstriction (α₁), activates RAAS → ↑ Na⁺/H₂O reabsorption.
Summarise the Renin-Angiotensin-Aldosterone System (RAAS).
Renin → Angiotensin I → (via ACE) → Angiotensin II → vasoconstriction, ↑ Na⁺/H₂O reabsorption, aldosterone release.
What is the overall goal of integrated cardio-respiratory-renal control?
Maintain homeostasis via neural and chemical signals integrating CV, respiratory, and renal systems.
